I am an industrial electronics engineering student and i m making my final year project on redundancy in PLC. So i need some detail:

1.Is siemen s7-300 PLC support redendancy or not????

2. In redundancy is it compulsory that both primary and secondary plc should be redendant support or only one is redundant enough???

3.Which protocol is most suitable????

4. And plz tell me about more parameters use in this projrct????

Please as soon as possible reply me itz urgrnt i m very thankful to that person

Hello Aiju;1. Yes, S7-300 CPUs can support redundancy, but not what is considederd "Hot" Redundancy (this is only achieved with a S7-400H system, in Siemens' world). You can setup a "Warm" Redundnacy application (slower reaction times, and responsability for the redundant programming will be in the programmer's hands) with a S7-300 pair based onthe Software Redundancy package:SIMATIC S7-300/S7-400 Software redundancy for SIMATIC S7

2. I do not quite understand this question. Both primary and standby PLCs are redundant to each other, each one can be master of the control systemat one time, but not together. See the decription of the redundant system in the manual above.

3. For software redundancy purposes you can use networks such as MPI, Profibus-DP or Industrial Ethernet. MPI is very slow, the other 2 require an additional CP cardin each PLC but offer a much better reaction time.

4. Again the best source for the parameters (hardware and software requirements) is in the manual suggested earlier. You will find a lot of help on the forum (look for existing threads on Software Redundancty using the search box at the right of this page) and if you decide to start using such a system many users have developped quite a lot of experience, and are willing to guide you.